azure-mgmt-* packages don't build

## Issue description

I've already worked through the update, but let's revert for now, because the newer `azure-mgmt-*` packages also break `nixops`.

cc @olcai @FRidh 

### Steps to reproduce

```
$ nix-build <nixpkgs> -A pythonPackages.azure-mgmt-storage
...
configuring
sed: can't read azure/mgmt/storage/storagemanagement.py: No such file or directory
...
```
